Composition and method for combatting fungi and mites containing triorganotin compounds

ABSTRACT

Tri-2-norbornyltin compounds of the general formulae   EFFECTIVELY COMBAT FUNGI AND MITES WHEN APPLIED TO OBJECTS, PARTICULARLY PLANTS, THAT ARE SUSCEPTIBLE TO ATTACK BY THESE ORGANISMS. The present compounds are particularly advantageous in that they are non-phytotoxic and therefore will not damage plants to which they are applied. In the foregoing formulae each R1 is individually selected from hydrogen and lower alkyl radicals, X is a chlorine, bromine, fluorine, hydroxyl, carboxylate, phenoxy, alkoxy (-OR2) or mercaptide (-SR2) radical wherein R2 represents an alkyl or aryl radical containing between 1 and 12 carbon atoms, inclusive and Y is an oxygen, sulfur, or a sulfate radical.

United States Patent [1 1 Gitlitz July 1,1975

[75] Inventor: Melvin H. Gitlitz, Edison, NJ.

[73] Assignee: M & T Chemicals Inc., Greenwich,

Conn.

22 Filed: July 16, 1973 21 Appl. No.: 379,745

Related U.S. Application Data [62] Division of Ser. No. 316,045, Dec.18, 1972, Pat. No.

Primary ExaminerAlbert T. Meyers Assistant ExaminerDale R. Ore

Attorney, Agent, or Firm-Robert P. Auber; Kenneth G. Wheeless; RobertSpector [57] ABSTRACT Tri-2-norbornyltin compounds of the generalformulae R 7 3 SHX and 1 R 3 Sn 2 Y effectively combat fungi and miteswhen applied to objects, particularly plants, that are susceptible toattack by these organisms. The present compounds are particularlyadvantageous in that they are nonphytotoxic and therefore will notdamage plants to which they are applied. In the foregoing formulae eachR is individually selected from hydrogen and lower alkyl radicals, X isa chlorine, bromine, fluorine, hydroxyl, carboxylate, phenoxy, alkoxy(-OR or mercaptide (SR radical wherein R represents an alkyl or arylradical containing between 1 and 12 carbon atoms, inclusive and Y is anoxygen, sulfur, or a sulfate radical.

11 Claims, No Drawings COMPOSITION AND METHOD FOR COMBATTING FUNGI ANDMIT ES CONTAINING TRIORGANOTIN COMPOUNDS This application is adivisional application of copending application Ser. No. 316,045, filedDec. 18, 1972 now U.S. Pat. No. 3,781,316.

This invention relates to a method for selectively controlling fungi andmites using tri-Z-norbornyltin compounds. The organisms against whichthe compounds are effective are responsible for a considerable portionof the annual damage to agricultural crops. Over the years fungi andmites have developed a resistance to many chemicals which had previouslybeen effective in combating them. The development of resistant strainshas mandated a search for new miticides and fungicides. Sometriorganotin compounds effectively control these pests; however many ofthese compounds are relatively non-selective when applied to desirableplant crops, in that while the organism attacking the plant may becontrolled, the plant itself is often killed or severely damaged.

SUMMARY OF THE INVENTION It has now been found that triorbornyltincompounds of the general formulae snx and effectively control fungi andmites yet do not damage plants to which efficacious amounts of thesecom-.

pounds are applied. In the foregoing formulae, each R is individuallyselected from the group consisting of hydrogen atoms and linear andbranched alkyl radicals containing between I and 8 carbon atoms, Xrepresents a radical selected from the group consisting of chlorine,bromine, fluorine, hydroxyl, carboxylate, phenoxy, alkoxy (--OR*), andmercaptide (SR wherein R represents an alkyl or aryl radical containingbetween I and 12 carbon atoms, inclusive and Y is an oxygen, sulfur, orsulfate radical.

DETAILED DESCRIPTION OF THE INVENTION wherein R represents a hydrocarbonradical selected from the group consisting of alkyl containing between Iand 6 carbon atoms, phenyl, ally] and vinyl. Preferably thetetraorganotin compound is dissolved in a suitable solvent or mixture ofsolvents to which a solution of the desired stannic halide is graduallyadded. Suitable solvents are liquid aromatic, aliphatic andcycoaliphatic hydrocarbons and halogenated hydrocarbons.

3 3 Sn-R Sn C].

a v l R Sn 01 R, 81101 The resultant trinorbornyltin chloride may be aliquid or solid at ambient temperature depending upon the substituent(s)represented by R and can readily be converted to other derivatives suchas the oxide, acetate, and sulfate using known reactions. The desiredanionic radical can be introduced by reacting the corresponding halideor oxide with the reagent indicated in the following table.

ORGANOTIN DESIRED DERIVATIVE REAGENT PRODUCT Chloride, BromideCarboxylic acid carboxylate or Iodide acid acceptor, e.g. e.g. acetatepyridine alkali metal salt of a carboxylic acid aqueous solution ofoxide (or alkali metal hydroxide hydroxide) alkali metal alkoxidealkoxide or alcohol acid acceptor alkali metal phenoxide phenoxide orphenol acid acceptor potassium fluoride or fluoride hydrofluoric acidalkali metal sulfide sulfide alkali metal sulfate sulfate mercaptan acidmercaptide acceptor Oxide (or hydroxide) carboxylic acid or carboxylateanhydride alcohol (or phenol) alkoxide (or phenoxide) hydrofluoric acidfluoride dilute (10-25 weight sulfate 7c) aqueous sulfuric acid hydrogensulfide sulfide alkyl or aryl mercaptan mercaptide The reactionconditions such as preferred solvents, temperatures and reaction timesfor preparing the derivatives summarized in the preceeding table areknown in the art and, therefore, do not require a detailed descriptionin the present specification. A comprehensive treatment of this subjectmatter is contained in an article by R. K. lngham et al. that appearedin the October, 1960 issue of CHEMICAL REVIEWS (p.p. 459-539). Thetrinorbornyltin compounds are liquids or solid materials at ambienttemperature, depending upon the type of substituents represented by R, Xand Y Tri-2-norbornyltin compounds effectively combat undesirable mitesand fungi without damaging the plants to which the compounds areapplied. A single application of these compounds can provide residualand extended control of fungi and mites for a considerable period oftime, the duration of which is dependent to some extent upon mechanicaland biological influences, including weather, but is sometimes as longas several months.

In preparing compositions for application to plants the organotincompound is often augmented or modified by combining it with one or morecommonly employed pesticide additives or adjuvants including organicsolvents, water or other liquid carriers, surface active dispersingagents or particulate and finely comminuted or divided solid carriers.Depending upon the concentration of the tin compound in thesecompositions, they can be employed either directly to control theorganisms or as concentrates which are subsequently diluted with one ormore additional inert carriers to produce the ultimate treatingcompositions. In compositions to be employed as concentrates, the tri-2-norbornyltin compound can be present at a concentration of from about 5to about 98 percent by weight. Other biologically active agents that arechemically compatible with the present tin compounds can also be added.

The optimum concentration of tin compounds to be employed as toxicant ina composition for application to the organism directly or by employingits habitat for food as carrier, may vary provided that the organism iscontacted with an effective dose of the toxicant. The actual weight ofcompound constituting an effective dose is primarily dependent upon thesusceptibility of a particular organism to the tin compound. Forcombating apple scab, good results are obtained with liquid or dustcompositions containing as little as 12.5 parts per million by weight oftoxicant. Compositions containing up to 90 percent by weight of toxicantcan be employed in the treatment of a mite-infested environment.

In the preparation of dust compositions, the tri-2- norbornyltincompound can be blended with many commonly employed finely dividedsolids, such as fullers earth, attapulgite, bentonite, pyrophyllite,vermiculite, diatomaceous earth, talc, chalk, gypsum, wood flour, andthe like. In such operations, the finely divided carrier is ground ormixed with the toxicant or wetted with a dispersion of the toxicant in avolatile liquid. Depending upon the proportions of ingredients, thesecompositions can be employed as concentrates and subsequently dilutedwith additional solid of the types indicated hereinbefore, to obtain thedesired amount of active ingredient in a comminuted composition adaptedfor the control of pests. Also, such concentrate dust compositions canbe incorporated in intimate admixture with surface active dispersingagents such as ionic and non-ionic emulsifying or dispersing agents toform spray concentrates. Such concentrates are readily dispersible inliquid carriers to form spray compositions or liquid formulationscontaining the toxicants in any desired amount. The choice of surfaceactive agent and amount thereof employed are determined by the abilityof the agent to facilitate the dispersing of the concentrate in theliquid carrier to produce the desired liquid composition. Suitableliquid carriers include water, methanol, ethanol, isopropanol, methylethyl ketone, acetone, methylene chloride, chlorobenzene, toluene,xylene, and petroleum distillates. Among the preferred petroleumdistillates are those boiling almost entirely unter 400F. at atmosphericpressure and having a flash point above about Alternatively, one or moretri-2-norbornyltin compounds can be dissolved in a suitablewater-immiscible organic liquid and a surface active dispersing agent toproduce emulsifiable concentrates which may be further diluted withwater and oil to form spray mixtures in the form of oil-in-wateremulsions. In such compositions, the carrier comprises an aqueousemulsion, i.e. a mixture of water-immiscible solvent, emulsifying agentand water. Preferred dispersing agents which may be employed in thesecompositions are oil soluble and include the condensation products ofalkylene oxides with phenols and organic and inorganic acids,polyoxyethylene derivatives of sorbitan esters, alkylarylsulfonates,complex ether alcohols, mahogany soaps and the like. Suitable organicliquids to be employed in the compositions include petroleumdistillates, hexanol, liquid halohydrocarbons and synthetic.organic'oils. The surface active dispersing agents are usually employedin the liquid dispersions and aqueous emulsions in the amount of fromabout 1 to about 20 percent by weight of the combined weight of thedispersing agent and the active toxicant.

When operating in accordance with the present invention, thetrinorbornyltin compound or a composition containing the compound can beapplied directly to the undesirable organism when mites are beingcontrolled, or to their habitat or food in any convenient fashion, i.e.by means of hand dusters or sprayers or by simple mixing with the foodto be ingested by the mites. Applications to the foliage of plants isconveniently carried out using power dusters, boom sprayers and spraydusters. When employed in this manner the compositions should notcontain any significant amounts of phytotoxic diluents. In large scaleoperations, dusts or low volume sprays may be applied from an aircraft.

The following examples represent preferred embodiments of the presentinvention, and are not intended to limit the scope thereof. All partsand percentages are by weight unless otherwise specified.

EXAMPLE 1 Preparation of tris-2-norbornyltin chloride a.2-Norbornylmagnesium Bromide A 25 c.c. portion of solution containing 50g. (0.286 mole) of exo-2-bromonorborane and c.c. of anhydroustetrahydrofuran was added to 8.35 g. (0.343 mole) of magnesium chipscontained in a reactor equipped with a reflux condenser, mechanicallydriven agitator and nitrogen inlet. The contents of the reactor wereheated to 40C. and the reaction initiated by the addition of a few dropsof ethylene dibromide. The remainder of the bromonorborane solution wasthen added dropwise over one hour while the reaction mixture was heatedto the boiling point. Heating was continued for 1.5 hours followingcompletion of the addition, at which time 200 cc. of anhydroustetrahydrofuran was added to dissolve the product. 2-norbornylmagnesiumbromide. The reaction mixture was then cooled to ambient temperature andthe liquid phase removed by decantation.

b. Butyltri-Z-norbornyltin A solution containing 19.2 g. (0.068 moles)of butyltin trichloride and 100 c.c. benzene was added over a 25 minuteperiod to 335 c.c. of the solution prepared as described in section a)which contained 0.67 moles of 2-norbornylmagnesium bromide per liter ofsolution. The temperature of the reaction mixture rose to 42C. duringthe addition. Following completion of the addition the reaction mixturewas heated to the boiling point for 20 minutes, stored atambienttemperature for about 16 hours with stirring, and finally heated to theboiling point for an additional hour. The reaction mixture was thenallowed to cool to ambient temperature, at which time a solution of 25g. ammonium chloride and 250 c.c. water was added to hydrolyze thereaction product. The organic phase which formed was separated and thewater removed using anhydrous magnesium sulfate. The solid material wasseparated by filtration and the solvents removed under reduced pressure.The viscous residue was converted to a white solid during a washing withcold methanol. The solid material was isolated, washed with coldmethanol and dried. The product contained 25.74 percent by weight oftin, compared with a calculated value of 25.73 percent forbutyltri2-norbornyltin.

c. Cleavage of butyltin-Z-norbornyltin A solution containing 9.9 g.(0.038 mole) of stannic chloride and 50 c.c. pentane was added over 15minutes to a stirred solution of butyltriQ-norbornyltin (17.5 g., 0.038mole) in 50 c.c. pentane. The reaction mixture was neither heated norcooled during the addition of the stannic chloride. The initiallycolorless solution turned yellow during the addition. The reactionmixture was then heated to the boiling point for 15 minutes, duringwhich time a white solid material precipitated. After cooling to roomtemperature the butyltin trichloride was extracted by the addition of 2c.c. of concentrated (12 normal) aqueous hydrochloric acid and 48 c.c.water. The resultant mixture ofa solid and two liquid phases wasfiltered to isolate the tris-2- norbornyltin chloride which was driedunder reduced pressure. The solid product was found to contain 26.77

percent by weight of tin and 7.86 percent by weight of chlorine. Thecalculated values are 27.00 and 8.06 percent, respectively.

EXAMPLE 2 Preparation of bis(tri-2norbornyltin) oxide A solutioncontaining 3.2 g. of sodium hydroxide, 25 c.c. of methanol and 25 c.c.of water was gradually added over five minutes to a stirred solutioncontaining l7.6 g. of tri-Z-norbornyltin chloride and 300 c.c. ofacetone. A white solid precipitated during the addition. following whichthe reaction mixture was heated to the boiling point with stirring forthirty minutes. A 500 c.c. portion of cold water was then added to thereaction mixture, which was subsequently cooled to C. by placing thereaction vessel in a mixture of ice and water. The solid material in thereaction mixture was isolated by filtration and washed using 500 c.c.portions of water containing 20 drops of an alkyl-aryl sulfonate wettingagent until the wash water was free of detectable chlorides. The driedsolid weighed l5.65 g. and was found to contain 28.79 percent by weightof tin. The theoretical tin content of bis(tri-2-norbornyltin) oxide is28.80 percent. The infra-red spectrum of the product showed anabsorption at 750 cm. indicating the presence of and Sn-O-Sn linkage.

BIOLOGICAL ACTIVITY OF TRl-ZNORBORNYLTIN DERIVATIVES I. GeneralEvaluation Methods Tri-2-norbornyltin chloride and bis(tri2-norbornyltin) oxide were evaluated in the form of sprayable compositionsprepared by dissolving or dispersing the compounds in a /10 weight ratiowater- /acetone mixture containing a small amount of a nonionicsurfactant. The resultant stock solutions or dispersions were thendiluted using a water-surfactant mixture to obtain the desiredconcentration of tin compound while maintaining the surfactantconcentration at parts per million (p.p.m.). Samples which proveddifficult to emulsify were homogenized using a colloid mill or tissuehomogenizer.

2. Evaluation of the Effectiveness of Tri-2-norbornyltin CompoundsAgainst Specific Organisms.

The efficacy of the triorganotin compounds of this invention asfungicides and miticides was investigated and the results are summarizedin the following section. The test organisms employed were powdery beanmildew, apple mildew. apple scab, leaf spot of rice and the two-spottedspider mite.

The rating system employed to determine control of the organisms wasbased on a numerical scale wherein a rating of 10 indicated 100% control(no surviving organisms or fungus) and a rating of 0 indicated nocontrol, i.e. the plant was heavily infested with the organism orfungus. The control rating employed for the fungi is a function of thefraction of total leaf which is unaffected by these fungi organisms.

A. Powdery Bean Mildew Tender green bean plants with fully expanded primary leaves are placed adjacent to plants infested with the powderymildew fungus (ersiphe polygoni) 48 hours prior to the application oftri-2-norbornyltin chloride or his (tri-2-norbornyltin) oxide. The tincompound is applied by placing the plants on a revolving turntable andspraying them with a formulation containing the triorganotin compound.When the spray deposit dries, the plants are placed in a greenhouse forbetween 7 and 10 days after which time the amount of mildew on theprimary leaves is rated. Untreated plants serve as controls, whichexhibit a rating of O. The formulations tested contained 100 and 20parts per million (p.p.m.) of his (tri-2-norbornyltin) oxide and 100, 50and 25 p.p.m. of tri-2-norbornyltin chloride.

Notes? "ratings of l\\U different plants.

None of the formulations tested were phytotoxic to the bean plants.

B. Apple Mildew Apple seeds which had been refrigerated for 60 days wereplanted in pasteurized soil. When the resultant seedlings were in thefifth leaf stage the plants were sprayed with a formulation containing50 ppm, of tri-Z-norbornyltin chloride. On the following day they wereplaced among plants that were heavily infested with apple mildew. Thesprayed plants were rated 14-21 days following the initial exposure tothe mildew (first rating), after which the plants were again sprayedwith the same formulation which had previously been employed. The ratingwas repeated 20 days and 35 days (second and third ratings,respectively) following the second spraying. None of the sprayed plantsexhibited any phytoxic effects.

Control Ratings C. Apple Scab Frozen apple leaves which were infestedwith conidia spores were soaked in cool water for about 30 minutes,following which the liquid phase was filtered through a single layer ofcheesecloth. A number of apple seedlings in the fifth leaf stage weresprayed with the water containing the dispersed conidia spores. Theseedlings were stored in a high humidity environment [relative humidity(R.H.) 100 percent] at ambient temperature for two days, after whichthey were stored at a temperature of 24 i 3C. for seven days, then inthe high humidity environment for between one and two days, and finallyat 24 i 3C. for to 15 days, during which time the infested leaves wereharvested. The leaves were extracted with cool water to prepare a stocksolution which when viewed under a microscope at 100 X magnificationexhibited a field containing not less than conidia spores.

The plants to be tested were sprayed with a liquid for mulationcontaining 250, 50 or 12.5 ppm. of tri-2- norbornyltin chloride. Theformulations were prepared as previously described. After the solventhad evaporated the leaves were sprayed with the suspension of conidiaspores prepared as described in the preceeding paragraph. The plantswere then placed in a high humidity (100% relative humidity) environmentat ambient temperature for two days, after which they were stored underconditions of ambient humidity and a temperature of 24 i 3C. untilevidence of apple scab was observed on the untreated control, asindicated by brownish lesions on the leaves. The results of the test aresummarized below.

Concentration of Control Organotin Compound (p.p.m.) Rating using theprocedure described in part A of this section. Once the spray had driedthe leaves of the plants were innoculated with a suspension ofhelminthosporium spores and placed in an incubation chamber for 24hours, then stored under ambient coonditions until lesions developed onthe leaves of control plants which had not been treated with theorganotin compound and which were innoculated with helminthosporiumspores and incubated concurrently with the treated plants. The treatedplants exhibited a control rating of 7 when the control plants becamecompletely infested (control rating O). E. Two-spotted Spider Mite Theleaves of bean plants were dipped into formulations containing adispersed form of either tri-Z- norbornyltin chloride orbis(tri'2-norbornyltin) oxide. The concentration of the organotincompound was 50 or 200 ppm. A number of nymph stage and adult spidermites were then transferred onto the upper surface of the plant leaves.The plants remained undistrubed at 24 3C. for between 8 and 12 daysfollowing exposure to the mites, at which time the control rating wasobtained by observing percentages of dead nymphs and adult mites.

Concentration of Tin Compound in Spray (p.p.m.) Control Rating Chloride200 I0 (A); 10 (N) Oxide 200 10 (A); l() (N) 50 l0 (A): 8 (N) A adultmites, N nymph stage mites None of the spray formulations employed werephytotoxic to the plants.

Although the compounds employed to determine biological activity weretri-2-norbornyltin chloride and bis(tri-2-norbornyltin) oxide, otherderivatives including fluorides, bromides, carboxylates, mercaptides,alkoxides, phenoxides, sulfides and sulfates are expected to be at leastequally efficacious in combating fungi and mites since it has been shownthat the anionic radical of the present triorganotin compounds,represented by X and Y in the foregoing generic formulae, have little,if any, effect on the degree of biological activity exhibited by thecompound unless the anion itself possesses significant biologicalactivity.

What is claimed is:

1. A non-phytotoxic composition for combating fungi and mites, saidcomposition comprising an inert liquid or inert solid carrier and afungicidally or miticidally effective amount ofa tri-Z-norbornyltincompound represented by the general formula Sn X wherein each R isindividually selected from the group consisting of hydrogen linear alkylcontaining between 1 and 8 carbons and branched alkyl containing between1 and 8 carbons, X is selected from the group consisting of chlorine,bromine, fluorine, hydroxyl, carboxylate, phenoxy, alkoxy (-OR andmercaptide (-SR wherein R is alkyl containing between I and 12 carbons,inclusive and Y is selected from the group consisting of oxygen, sulfurand sulfate.

2. The non-phytotoxic composition of claim 1 wherein each R is hydrogen.

3. The non-phytotoxic composition wherein X is halogen.

4. The non-phytotoxic composition wherein Y is oxygen.

5. The non-phytotoxic composition wherein X is hydroxyl.

6. A method for controlling fungi and mites which comprises contactingsaid fungi and mites with a fungicidally or miticidally effective amountof a compound of the formula of claim 1 of claim 1 of claim 1 whereineach R is individually selected from the group consisting of hydrogenlinear alkyl containing between 1 and 8 carbons and branched alkylcontaining between 1 and 8 carbons, X is selected from the groupconsisting of chlorine, bromine, fluorine, hydroxyl, carboxylate,phenoxy, alkoxy (OR*) and mercaptide (SR wherein R represents an alkylcontaining between 1 and 12 carbon, inclusive and Y is selected from thegroup consisting of oxygen, sulfur and sulfate.

7. A method according to claim 6 wherein each R is hydrogen.

8. A method according to claim 6 wherein X is halogen.

9. A method according to claim 6 wherein Y is oxygen.

10. A method according to claim 6 wherein X is hydroxyl.

11. A method according to claim 6 wherein the compound is applied to aplant which is susceptible to attack by fungi and mites.

1. A NON-PHYTOTOXIC COMPOSITION FOR COMBATING FUNGI AND MITES, SAIDCOMPOSITION COMPRISING AN INERT LIQUID OR INERT SOLID CARRIER AND AFUNGICIDALLY OR MITICIDALLY EFFECTIVE AMOUNT OF A TRI-2-NORBORNYLTINCOMPOUND REPRESENTED BY THE GENERAL FORMULA
 2. The non-phytotoxiccomposition of claim 1 wherein each R1 is hydrogen.
 3. Thenon-phytotoxic composition of claim 1 wherein X is halogen.
 4. Thenon-phytotoxic composition of claim 1 wherein Y is oxygen.
 5. Thenon-phytotoxic composition of claim 1 wherein X is hydroxyl.
 6. A methodfor controlling fungi and mites which comprises contacting said fungiand mites with a fungicidally or miticidally effective amount of acompound of the formula
 7. A method according to claim 6 wherein each R1is hydrogen.
 8. A method according to claim 6 wherein X is halogen.
 9. Amethod according to claim 6 wherein Y is oxygen.
 10. A method accordingto claim 6 wherein X is hydroxyl.
 11. A method accorDing to claim 6wherein the compound is applied to a plant which is susceptible toattack by fungi and mites.